Adult outcomes of youth irritability: a 20-year prospective community-based study.
Irritability is a widely occurring DSM-IV symptom in youths. However, little is known about the relationship between irritability in early life and its outcomes in mid-adulthood. This study examines the extent to which youth irritability is related to adult psychiatric outcomes by testing the hypothesis that it predicts depressive and generalized anxiety disorders. The authors conducted a longitudinal community-based study of 631 participants whose parents were interviewed when participants were in early adolescence (mean age=13.8 years [SD=2.6]) and who were themselves interviewed 20 years later (mean age=33.2 years [SD=2.9]). Parent-reported irritability in adolescence was used to predict self-reported psychopathology, assessed by standardized diagnostic interview at 20-year follow-up. Cross-sectionally, irritability in adolescence was widely associated with other psychiatric disorders. After adjustment for baseline emotional and behavioral disorders, irritability in adolescence predicted major depressive disorder (odds ratio=1.33, 95% confidence interval [CI]=1.00-1.78]), generalized anxiety disorder (odds ratio=1.72, 95% CI=1.04-2.87), and dysthymia (odds ratio=1.81, 95% CI=1.06-3.12) at 20-year follow-up. Youth irritability did not predict bipolar disorder or axis II disorders at follow-up. Youth irritability as reported by parents is a specific predictor of self-reported depressive and anxiety disorders 20 years later. The role of irritability in developmental psychiatry, and in the pathophysiology of mood and anxiety disorders specifically, should receive further study.